Intravascular sensing device

ABSTRACT

A system for detecting electrical activity within a patient&#39;s heart comprising an elongated intravascular device, such as a catheter or guidewire, having at least one bipolar electrode pair on a distal section of the elongated device to intravascularly detect electrical activity within the patient&#39;s heart. The catheter or guidewire preferably has a tubular shaft formed of braided strands which include a plurality of insulated conductors which are electrically connected to the bipolar electrodes.

RELATED APPLICATIONS

This is a continuation application of application Ser. No. 08/636,509filed on Apr. 19, 1996 now U.S. Pat. No. 5,682,885, which is acontinuation of application Ser. No. 08/188,619 now U.S. Pat. No.5,509,411 filed Jan. 27, 1994, which is a continuation-in-part ofapplication Ser. No. 08/010,818, filed Jan. 29, 1993 now abandoned,application Ser. No. 08/043,449, filed Apr. 5, 1993 now abandoned, andapplication Ser. No. 08/057,294, filed May 5, 1993 now abandoned, whichare incorporated herein in their entirety by reference.

BACKGROUND OF THE INVENTION

This invention generally relates to the detection of electrical activityor signals within a patient's heart and particularly for determining thesource of signals causing arrhythmia.

Prior methods for treating a patient's arrhythmia include the use ofantiarrhythmic drugs such as sodium and calcium channel blockers ordrugs which reduce the Beta-adrenergic activity. Other methods includethe surgically sectioning the origin of the signals causing thearrhythmia or the conducting pathway for such signals. More frequently,however, to terminate the arrhythmia, the heart tissue which causes thearrhythmia is destroyed by heat, e.g. applying a laser beam or radiofrequency (RF) energy to a desired location on the patient'sendocardium.

In the latter instance, the location of the site causing the arrhythmiamust be accurately known in order to be able to contact the desiredlocation with a tissue destroying device. A major problem of ablatingthe site of the origin of the signals or a conductive pathway is toaccurately determine the site so that an excessive amount of good tissueis not destroyed along with the arrhythmogenic site to ensure that thearrhythmia does not return. For example, the average arrhythmogenic siteconsists of about 1.4 cm² of endocardial tissue, whereas a re-entrantsite might be much larger. RF ablation techniques produce lesions about0.5 cm² in diameter, so several lesions may have to be formed tocompletely ablate the area of interest. If the arrhythmogenic orre-entrant site is not accurately mapped, much good tissue surroundingthe site will be unnecessarily destroyed.

A variety of methods have been used to detect electrical activity withina patient's heart to facilitate the mapping of electrical activitycausing the arrhythmia. A number of U.S. Patents describe the use ofelongated intravascular signal sensing devices which are advancedthrough the patient's vasculature until the distal portions of thesensing devices are disposed within one of the heart chambers with oneor more electrodes on the distal portion in contact with the endocardiallining. While this procedure is widely used, it does not always allowthe site of arrhythmogenic signals to be accurately determined.

The literature also mentions advancing an intravascular signal sensingdevice within a patient's coronary artery or coronary sinus or a cardiacvein. However, these methods appear to be experimental and have not beenwidely used clinically.

What has been needed is a method and system for accurately detecting thesource of signals which cause the arrhythmia.

SUMMARY OF THE INVENTION

This invention is directed to an elongated intravascular sensing devicefor detecting electrical activity of a patient's heart within a vein orartery thereof, and particularly the electrical activity which causesarrhythmia.

The intravascular sensing device of the invention comprises an elongatedshaft with a proximal section and a distal section, with the distalsection of the shaft being configured so as to be advanceable throughthe patient's coronary anatomy. The distal section is provided with atleast one and preferably a plurality of bipolar electrode pairs spacedalong a length of the distal section. Up to 20 or more bipolar electrodepairs may be provided along the distal section of the shaft.

The shaft of the intravascular sensing device is preferably formed of aplurality of insulated electrical conductors braided or wound into anelongated tubular member, although not all of the strands which make upthe tubular member need be electrical conductors. The insulation onseparate conductors is exposed under each of the sensing electrodes sothat an electrical connection can be made. The electrical connection maybe secured by means of a suitable solder or brazing material, and theelectrodes may be secured to the underlying tubular member by a suitablemeans such as an adhesive to ensure maintenance of electrical contactwith the exposed conductors. The proximal ends of the electricalconductors are electrically connected to a multi-pin connector on theproximal end of the shaft which is configured to be connected to areceiving member in electrical communication with a display unit.

A plastic jacket, preferably a lubricous polymer such as a thermoplasticfluoropolymer, is applied to the length of the braided tubular memberwith a slight overlap of the jacket over the edges of the individualelectrodes to prevent exposure of a sharp metallic edge which can causedamage when the elongated device is advanced through blood vessels.

The elongated device of the invention may be in the form of a guidewirewhich has an elongated core member disposed within tubular member formedby the braided electrical conductors. The distal section of theguidewire may have a flexible tip coil which is distal to the length onwhich the bipolar electrodes are mounted and which is disposed about thedistal extremity of the core member. The distal end of the core membermay be manually shapable by the physician to facilitate steering thedistal portion of the elongated sensing device within the patient'svasculature by torquing the proximal end which extends out of thepatient during the procedure. A smooth rounded tip or plug is providedat the distal end of the coil to avoid damage when being advancedthrough the patient's vasculature. A safety or shaping ribbon may extendfrom the distal end of the core member to the rounded tip inconventional guidewire fashion.

The elongated device of the invention may also be in the form of acatheter which has an elongated inner lumen extending from the proximalend to a discharge or guidewire port in the distal end of the device.The distal end of the catheter may be provided with a soft tip tominimize traumatic engagement with a blood vessel wall when beingadvanced therein. In one presently preferred embodiment the inner lumenof the catheter form of the device of the invention is configured toallow the passage therethrough of a conventional guidewire or aguidewire version of the device of the invention which allows signaldetection at different locations within the same blood vessel or branchthereof.

When using the intravascular device of the invention, it is firstintroduced percutaneously or by means of a cut-down into one of thepatient's major peripheral arteries or veins (e.g. the femoral vein orartery) and advanced through the patient's vasculature to one or moredesired locations within the veins or arteries of the patient's heart.The distal section of the elongated device of the invention ispreferably configured to be advanceable within a blood vessel having anative inner diameter of less than about one millimeter and preferablyless than 0.75 mm. A plurality of such devices may be introduced intothe patient's vascular system with one or more devices within thepatient's cardiac veins and one or more devices within the patient'scoronary arteries.

Electrical signals from the patient's heart are received by the one ormore electrode pairs on the distal section in bipolar mode andtransmitted through the electrical conductors attached to the individualelectrodes to multipin connectors on the proximal ends of the shafts.The position of an elongated sensing device of the invention within thearteries or veins of the patient's heart may be adjusted to optimizesignal reception by the electrodes on the distal section of the deviceand to better detect electrical activity.

It is frequently desirable to provide a device within the patient'sheart chambers with electrodes which provide pacing signals. Thisgreatly facilitates the detection of the arrhythmogenic site orconducting pathways for electrical signals.

The elongated device of the invention provide substantially improvedreception of electrical activity within the patient's heart withoutinterference from electrical activity from other regions of thepatient's heart. This improved accuracy greatly facilitates the mappingof the electrical activity which in turn allows more accurate ablation.These and other advantages will become more apparent from the followingdetailed description of the invention and the accompanying exemplarydrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an elevational view of a guidewire embodying features of theinvention.

FIG. 2 is an enlarged longitudinal cross-sectional view of a distalportion of the guidewire shown in FIG. 1.

FIG. 3 is an enlarged longitudinal cross-sectional view of the distalportion of a guidewire similar to that shown in FIG. 2 but having aplurality of braided layers.

FIG. 4 is a transverse cross-sectional view of the distal portion of theguidewire shown in FIG. 3 taken along the lines 4--4.

FIG. 5 is a longitudinal cross-sectional view of an intermediate portionof the guidewire shown in FIG. 1 taken along the lines 5--5.

FIG. 6 is a longitudinal cross-sectional view of the an extension of theproximal end of the guidewire shown in FIG. 1 taken along the lines6--6.

FIG. 7 is an elevational view, partially in section, of a catheterembodying features of the invention.

FIG. 8 is a transverse cross-sectional view of the catheter shown inFIG. 7 taken along the lines 8--8.

FIG. 9 is a schematic view of a patient's coronary arteries withguidewires shown in FIG. 1 disposed within the right coronary artery andthe anterior interventricular branch of the left coronary arteries.

FIG. 10 is a schematic view of a patient's coronary arteries and thegreat cardiac vein with guidewires as shown in FIG. 1 disposed withinthe anterior interventricular branch of the left coronary artery and thegreat cardiac vein.

FIG. 11 is a longitudinal cross-sectional view of an alternativeguidewire construction embodying features of the invention.

FIG. 12 is an elevational view, partially in section, of an alternativeguidewire construction.

FIG. 13 is an elevational view, partially in section, of an alternativecatheter construction embodying features of the invention.

FIG. 14 is an enlarged elevational view partially in section of thedistal portion of the catheter shown in FIG. 13.

FIG. 15 is a schematic representation of responses of bipolar electrodeson separated intravascular devices from an essentially planar wavefront.

FIG. 16 is a schematic representation of bipolar electrodes on separatedintravascular devices from a circular wave front.

FIG. 17 is an electrocardiogram using a guidewire to detect electricalactivity on the bipolar mode.

DETAILED DESCRIPTION OF THE INVENTION

Reference is made to FIGS. 1-5 which schematically illustrate anembodiment of the invention wherein the elongated device 10 is the formof a guidewire. The elongated device 10 includes shaft 11 with a distalsection 12 and a proximal section 13. The shaft 11 is formed of abraided tubular member 14 formed of a plurality of electrical conductors15. The distal section 12 of the shaft 11 is provided with a pluralityof bipolar electrode pairs 16, each pair of which includes electrodes 17and 18. A core member 19 is disposed within the inner lumen of thebraided tubular member 14 and extends beyond the distal end thereof. Adistal coil 20 is disposed about and secured by suitable means, such asbrazing, soldering or an appropriate adhesive, to the distal extremityof the core member 19 and is provided with a smooth rounded distal tip21 formed by joining the distal tip of the coil 20 to the distalextremity of the core member 19. The distal extremity of the core member19 may be flattened into a rectangular cross-section.

FIG. 2 illustrates a single braided layer with sixteen strands. However,when a higher number of electrode pairs 16 are used, e.g. sixteen ormore, a plurality of braided layers may be required, as depicted in FIG.3. As shown in this drawing, the outer braided layer 22 terminates at alocation proximal to that of the intermediate layer 23 and theintermediate layer terminates at a location proximal to the innermostlayer 24 to facilitate securing and electrically connecting theelectrodes 17 and 18 to the individual electrical conductors 15 as shownin FIG. 4. Some of the strands in the layers may not be conductors andbe formed of polymer materials such as nylon.

The proximal section 13 of the shaft 11 as shown in FIG. 1 has twoextensions 26 and 27 which have multi-pin connectors 28 and 29 on theproximal ends thereof with each of the electrical conductors 15 beingelectrically connected to a separate pin. Details of proximal extension26 is depicted in FIG. 6. A sixteen pin connector is schematically shownin FIG. 6 but connectors having a higher or lower number of pins may besuitable.

FIGS. 7 and 8 schematically illustrate another presently preferredembodiment of the invention in the form of a catheter 30. In thisembodiment, the catheter shaft 31 has an inner lumen 32 defined by aninner tubular element or lining 33 which is preferably formed oflubricous material such as Teflon®. A tubular member 34 is disposedabout tubular lining 33 and is formed of at least one braided layer 35.A plurality of the strands making up each of the braided layers areinsulated electrical conductors 38 which are electrically connected toindividual electrodes 39 and 40 of electrode pairs 41 as in thepreviously described embodiment. While not shown in the drawing, aplurality of braided layers may be required with more than eightelectrode pairs 41. As in the previous embodiment, when a plurality ofbraided layers are employed, the outer braided layer should terminate ata location proximal to that of the intermediate layer and theintermediate layer should terminate at a location proximal to the innerlayer to facilitate securing and electrically connecting the electrodes39 and 40 to the individual electrical conductors 38. Some of thestrands in each of the layers may be formed of other materials such asnylon. An outer jacket 42 extends the length of the shaft 31 and theportion of the jacket extending beyond the distal end of the braidedtubular member 34 is tapered to provide a nontraumatic flexible distaltip 43. As in the previously described example, the outer jacket 42overlaps the edges of the electrodes 39 and 40 to avoid exposing a sharpmetal edge when advancing the catheter through a patient's blood vessel.

The catheter 30 may be used by itself to detect electrical signalswithin the patient's coronary veins or arteries with the multipleelectrode pairs 41 as in the previous embodiment. Additionally, thecatheter may also be used to direct fluids containing cardioplegicmaterials such as iced saline, solutions of KCl, lidocaine,procaineamide hydrochloride and the like to areas of the patient's heartwhich are suspected to be the origin of or conduct the aberrant signals.If the arrhythmia stops upon the delivery of such cardioplegic agents,then the operator is assured that the artery or vein through which theagent is delivered leads toward or away from the region of the patient'sheart which is to be ablated in order to terminate the arrhythmia. Thesignal reception by the electrode pairs 41 are essentially the same asin the previously described guidewire embodiment.

The catheter 30 may also be used in conjunction with a guidewire 44(shown in phantom) as illustrated in FIGS. 7-8. The catheter 30 may bepositioned at a first location within a coronary artery or cardiac veinof the patient with the guidewire 44, which has a plurality of bipolarelectrode pairs 45 as in the previously discussed embodiment, disposedwithin the inner lumen of the catheter 30 and the distal section thereofextending out the port 46 in the distal end of the catheter into thepatient's blood vessel. Adjustments in the relative locations of theguidewire 44 and catheter 30 can be easily made by moving the guidewire44 through the inner lumen 32 of the catheter 30 or moving the catheterover the guidewire or both.

When using a femoral artery or femoral vein approach to the patient'sheart, it is frequently helpful to utilize a guiding catheter to guidethe catheter or guidewire of the invention to the coronary artery ostiumor the coronary sinus ostium. Such guiding catheters have speciallyshaped distal tips to facilitating the seating thereof within thedesired ostium, thus eliminating the trouble of directing a catheter orguidewire of the invention into the desire ostium.

The bipolar electrodes are circular bands about 0.25 to about 1 mm inwidth and are preferably made from conducting material which isbiocompatible with the body fluids such as gold. The electrodes of theelectrode pairs are spaced from each other by about 0.5 to about 2 mm,preferably about 0.75 to about 1.25 mm, and the spacing between thebipolar electrode pairs is about 2 to about 10 mm, preferably about 7 toabout 8 mm.

The overall length of the intravascular devices of the invention mayrange from about 80 to about 300 cm, typically about 135 to about 175 cmfor delivery through the femoral artery or vein and about 90 to about120 cm for delivery through the brachiocephalic artery or internaljugular vein. If the guidewire is to be advanced through the inner lumenof the catheter it should be longer than the catheter by about 20 toabout 40 cm. The distal section of the catheter is about 10 to about 50cm in length and is configured to be readily advanceable through apatient's coronary arteries or cardiac veins. The outer diameter of thecatheter should be less than about 0.055 inch (1.4 mm) and preferablyabout 0.035 inch (0.89 mm). The inner lumen 32 is about 0.012 to about0.022 inch (0.3-0.56 mm) in diameter to facilitate the reception andadvancement of a guidewire therethrough. The distal section of theguidewire is about 15 to about 40 cm in length and about 0.008 to about0.022 inch (0.2-0.56 mm) in outer diameter to facilitate advancementthrough the coronary arteries and cardiac veins of a human being havingnatural diameters of less than 0.04 inch (1 mm), preferably less than0.03 inch (0.75 mm). The distal coil on the guidewire is about 2 toabout 10 cm in length and is formed of wire about 0.0003 to about 0.006inch (0.008-0.153 mm) in diameter. The core member of the guidewire maybe tapered along its distal section in a conventional guidewireconstruction. The flattened distal portion has a rectangular transversecross section of about 0.002 by about 0.006 inch (0.051-0.15 mm).

To the extent not previously described, the materials of construction ofthe various guidewire and catheter parts may be formed of conventionalmaterials. The electrical conductors may be electrical grade copper wireabout 0.005 inch (0.13 mm) in diameter which are provided with a thininsulated jacket or coating of polyimide or other suitable insulator.The outer jacket may be a thermoplastic fluoropolymer such as THV whichis available from the 3M Corporation. The distal tip coil on theguidewire form of the invention is preferably formed of platinum tofacilitate fluoroscopic observation thereof within the patient, but itmay be formed in whole or in part with other material such as stainlesssteel, titanium, palladium, niobium, iridium, rhodium and alloysthereof. The core wire of the guidewire may be formed of stainless steelor a superelastic NiTi type alloy, with the latter preferably having astable austenite phase at body temperature and exhibiting a stressinduced austenite-to-martensite phase transformation. Proximal anddistal sections of the core member may be formed of different materialsso as to provide a stronger proximal section for greater pushability anda more flexible distal section to facilitate passage through tortuouscoronary anatomy.

One presently preferred method of using the elongated intravasculardevices of the invention as shown in FIG. 9 wherein the distal portion11 of the guidewires 10 such as shown in FIG. 1 are disposed within theright coronary artery 47 and the anterior interventricular branch of theleft coronary artery 48. As Indicated, the electrode pairs 16 on thedistal portion 11 extend along a major portion of the arteries. Theindividual intravascular devices may be moved within the arteries asneeded to optimize the signals received. While not shown in thedrawings, the distal tip with the coil 20 may be shaped to facilitateentry into a side branch of the coronary artery.

Another method is depicted in FIG. 10 wherein one of the elongatedintravascular devices 10 of the invention are disposed within the greatcardiac vein 49 and another is disposed within the anteriorinterventricular branch of the left coronary artery 48. A thirdintravascular device might also be deployed within the right coronaryartery 47 as shown to provide a more comprehensive mapping of thepatient's heart. As in the prior method the individual guidewires orother intravascular sensing devices may be moved within the artery orvein to better receive electrical activity.

An alternative embodiment of the invention in the form of a guidewire 50is shown in FIG. 11 which has a distal portion 51 with bipolarelectrodes 52 and 53, an intermediate portion 54 and a proximal portion55. A core member 56 extends through the inner lumen 57 of the guidewire10 from the proximal end to at least the distal portion 51. The distalbipolar electrode 52 is electrically secured to the core member 56 bysolder 58 and the proximal bipolar electrode 53 is secured by solder 59to electrical conductor 60 which may be an insulated wire or ribbon. Theproximal end of the electrical conductor 60 is secured by solder 61 toconductive metal tube 62 (e.g. hypotubing) which is electricallyisolated from the core member 56. The exterior surface of the coremember 56 and the exterior of the conductive metal tube 62 should beprovided with an insulating jacket or coating to maintain the electricalisolation therebetween. The core member 56 and the conductive metal tube62 are preferably secured together at one or more locations by aninsulating adhesive to facilitate the torqueability of the overallguidewire assembly. Preferably, they are secured at least at the distalend of the metal tube 62.

A coil 63 is disposed about core member 56 proximal to the bipolarelectrode pair 52 and 53 and it is secured to the core member by asuitably adhesive 64 or solder or weld. The coil 63 is preferably formedat least in part by a highly radiopaque biocompatible metal, e.gplatinum, rhodium, palladium, tungsten, gold, silver or alloys thereof,to facilitate the fluoroscopic observation thereof when disposed withinthe vasculature of a patient. A palladium-tungsten alloy is preferred.The core member 56 and the coil 63 provide shapeability to the distalportion 51 of the guidewire 50 to facilitate advancement thereof intoside branches of a patient's vasculature. An insulating member 65 isdisposed between the coil 63 and the proximal bipolar electrode 53 andan insulating member 66 is disposed between electrodes 52 and 53.

An inner tubular member 67 may be disposed within the distal section toprovide support to the electrodes 52 and 53 and inner tubular member 68may be disposed within the coil 63 to likewise provide support thereto.A suitable material is thin walled polyimide tubing which is commonlyemployed in intravascular catheters. A torquing knob 69 is provided onthe proximal end of core member 56.

The guidewire 50 may be of conventional intravascular guidewireconstruction. The overall length is about 150 to about 200 cm, theproximal OD of the core member 56 is typically about 0.013 inch and thedistal OD about 0.006 inch which may be further reduced to 0.003 inch.The core member 56 may be ground through one or more transitions to thesmaller OD sections. The core member 56 and particularly the distalportion thereof may be formed of a superelastic alloy such as NiTI whichhas a stable austenite phase at body temperature.

Another alternative guidewire embodiment of the invention is shown inFIG. 12. In this embodiment the guidewire 70 has a shaft 71 formed ofwoven or braided conductors 72 which are preferably insulated alongtheir length and which extend to the proximal end of the shaft. Aplurality of bipolar electrode pairs 73 with each pair having a proximalelectrode 74 and a distal electrode 75. Each of the electrodes areelectrically connected to a separate electrical conductor 72 by suitableconductive solder 76. While it is preferable that the conductors areinterwoven into the tube forming the shaft 71, the conductors may betwisted or wound. In the latter case the inner and outer layers of wireswould be laid out diagonally but the conductors of one layer would belaid in the opposite direction to that of the conductors in the otherlayer. Usually, the wound or twisted conductors are secured together bysuitable adhesive, whereas with the interwoven conductors there issufficient interlocking of the conductors that adhesives are not usuallyneeded. An insulating jacket 78 is provided about the catheter shaft 71.

The core member 77 extends through the interior of the guidewire shaftfrom the proximal end to the distal end thereof where it is secured tothe distal tip or plug 79 of the guidewire 70. A helical coil 80 isdisposed about a distal portion of the core member 77 and is secured atits distal end to the distal tip or plug 79 and at its proximal end byadhesive 81. The coil 80 is preferably formed at least in part by aradiopaque material such as those previously discussed. The core member77 may be configured as in the previous embodiments.

It is within the ambit of this invention that the intravascular sensingdevice be introduced into a femoral artery or a femoral vein (or otherconvenient body access site) and be advanced through the patient'svasculature to the coronary veins or arteries. Once the intravasculardevice is situated in the proper location in the coronary vasculature,electrical activity may be received in any way that is appropriate forthe specific situation. The catheter or guidewire may be moved toanother location and another set of signals received. It should beapparent that since each electrode mounted on the distal section of thesensing device is individually brought out via the woven wires orfilaments to the electrical connection at the proximal end, that eachelectrode may be used in conjunction with any other electrode in abipolar mode. The sensing devices may be used in multiples, e.g., asensing device in each of the major coronary veins and arteries, asshown in FIGS. 9 and 10, to provide an overall and complete electricalmap of the heart. In this way, arrhythmic foci may be readily locatedand therapeutic action taken.

FIGS. 13 and 14 illustrate a catheter assembly 90 which embodies anadditional aspect of the present invention directed to an intravascularcatheter 91 for sensing electrical activity within a patient's coronaryor cardiac blood vessels. As in the prior embodiments the bipolarelectrodes 92 and 93 are electrically connected to individual electricalconductors 94 which are woven or wound to form the tubular shaft 89 ofthe catheter 91. All of the strands which are wound to form the shaft 89need not be conductors 94 but may be strands of polymeric materials suchas Dacron, nylon, silk or other natural or synthetic polymeric material.When there are more than 16 electrodes and thus more than 16 electricalconductors, multiple woven layers may be employed. FIG. 14 illustratesin more detail the connection of electrical conductors 94 to theindividual electrodes 92 and 93. The electrical conductors 94 aretypically electrical grade copper wires of suitable outer diameter suchas about 0.004 to about 0.01 inch (0.10-0.25 mm). The conductors 94 maybe formed of other conducting materials such as silver, gold andplatinum. A suitable insulating material to coat the conductors 94 ispolyimide which minimizes cross talk and which can be applied in verythin layers. As in the other embodiments of the invention the conductors94 may be woven or merely wound, but preferably are woven.

The inner lumen 95 of the catheter 91 is configured to slidably receivea guidewire to facilitate the advancement of the catheter over theguidewire and preferably has at least in the distal portion thereof adiameter about 0.002 to about 0.005 inch (0.051-0.127 mm) greater thanthe guidewire which is to be disposed therein. For guidewire having ODof about 0.016 to about 0.018 inch (0.41-46 mm), the inner lumen 95would be about 0.018 to about 0.023 inch (0.46-0.58 mm). The OD of thecatheter may range from about 0.03 to about 0.1 inch (0.76-2.54 mm) butpreferably is about 0.03 to about 0.05 inch (0.076-1.27 mm),particularly 0.035 to about 0.040 inch (0.89-1.02 mm).

The proximal portion 96 of the catheter 91 makes up about 70 to about95% of the total length of the catheter with the intermediate portion 97and the distal portion 98 which has the sensing electrodes 92 and 93being the remainder. Preferably the catheter 91 has decreasing stiffnessfrom the proximal portion 96 to the intermediate portion 97 and thedistal portion 98 to facilitate the advancement of the catheter 91within the patient's vasculature. The exterior surface of the catheter91 and the surface defining inner lumen 95 may be formed of lubricousmaterials or hydrophilic materials which become lubricous whencontacting aqueous based fluids. Polysulfones and polyfluoroalkanes areexamples of suitable lubricous polymers and polyvinylpyrrolidone,polyethylene oxide and acrylate-based polymers of examples of suitablehydrophilic polymers.

The proximal end of the catheter 91 may be provided with a multiple armadapter 99 as shown in FIG. 13 with one arm 100 which is configured toreceive a syringe for delivering fluid into the inner lumen 95 and asecond arm 101 which is provided with an electrical connector 102 whichis electrically connected to the electrical conductors 94. The centralarm 106 facilitates entry of a guidewire (not shown) into the innerlumen 95. The catheter 91 may be advanced into position within thepatient's vascular system, i.e. either the coronary arteries or thecardiac veins, over a guidewire which may or may not have electrodes inaccordance with the invention to detect electrical activity therein. Ifthe guidewire over which the catheter is advanced into the patient'svasculature does not have sensing electrodes on its distal extremity, itmay be withdrawn when the catheter is in its desired position and aguidewire such as shown in FIG. 4 may be advanced through the innerlumen 95 of the catheter 91 and out the port 103 in the distal end ofthe catheter to a more distal position with the blood vessel.

Once the arrhythmogenic site or conductive pathway causing an arrhythmiais located by detecting the electrical activity, means can be advancedthrough the inner lumen 95 of a catheter of the invention to occlude anarterial passageway which feeds the arrhythmogenic site or conductivepathway so as to terminate the arrhythmia.

FIG. 15 represents an idealized output from a plurality of electrodepairs 110 and 111 on two separate intravascular devices (not shown)disposed in different, generally parallel coronary blood vessels, e.g. acoronary artery and the companion vein, to a nearly planar wave front112 approaching on end to the intravascular devices. The bipolarresponse 113 and 114 to the wave front 111 from each electrode pair 110and 111 is shown adjacent thereto, and as indicated, all of theresponses are essentially identical, except for the time-of-occurrence,because the wave front reaches all of the electrodes at the same angle.Changes in tissue properties, e.g. due to an infarct, adjacent thecatheters may retard the passage of the wave front and as a resultdistort the shape of the output.

FIG. 16 represents an idealized response from a plurality of electrodepairs 120 and 121 on two separate intravascular devices (not shown)disposed in different generally parallel coronary blood vessels, as inFIG. 10, but the wave front 122 originates from a site between and inclose proximity to the catheters. The idealized wave front 121 iscircular and the size and polarity of the responses 123 and 124 to theexpanding wave front varies according to the angle of incidence betweenthe wave front and the electrode pair. An arrhythmogenic site wouldcreate a less than ideal wave front which can be readily detected by theplurality of electrodes 120 and 121.

The time of occurrence and directional information obtained from theresponse from the wave front may be used to determine the origin of theectopic beat.

EXAMPLE

A guidewire was constructed using a woven tubular braid of sixteeninsulated electrical conducting wires, eight woven counterclockwise andeight woven clockwise. Gold metal electrodes 0.01 inch in width weremounted onto the distal end of the shaft about 0.5 inch (12.7 mm) apartwith each attached to one of the electrical conducting wires. Theoverall length of the guidewire was about 240 cm. An eight connector DINplug was installed at the proximal end of the guidewire. The guidewireassembly was 0.018 inch (0.46 mm) in diameter at the distal end, 0.026inch (0.66 mm) in diameter at the midsection, and 0.032 inch (0.81 mm)at the more proximal end.

The guidewire was introduced into the coronary artery of a live dogusing a 7 French coronary guide catheter. A pacer lead having fourelectrodes was disposed within the heart chamber and was used to pace aventricular beat so that the electrical activity as a result of thatpacing could be monitored intravascularly using the guidewire of theinvention. FIG. 17 is an electrocardiogram produced using the guidewireof the invention which depicts two pulses from that animal test inbipolar mode.

The present invention has been described herein in terms of certainpreferred embodiments but various modifications may be made to thepresent invention without departing from the scope thereof.

What is claimed is:
 1. An intravascular assembly, comprising:a) anelongated intravascular catheter having an elongated shaft, proximal anddistal ends, a port in the proximal end, a port in the distal end, aninner lumen extending within the elongated shaft to and in fluidcommunication with the ports in the proximal and distal ends, a distalsection configured to be advanceable through a coronary artery orcardiac vein of a patient's heart, a plurality of electrodes mounted onand longitudinally spaced along a length of the distal section thereofand a plurality of electrical conductors extending along the cathetershaft with each electrode being electrically connected to a separateelectrical conductor; and b) an elongated intravascular guidewire deviceslidably disposed within the inner lumen of the elongated intravascularcatheter, comprising:an elongated shaft having proximal and distalsections with the distal section being configured to be advanceablethrough a coronary artery or a cardiac vein of a patient's heart andhaving a core member extending to a distal extremity thereof and formingat least in part a shapeable flexible guiding tip.
 2. The intravascularassembly of claim 1 wherein the guidewire device includes at least onepair of bipolar electrodes mounted on the distal shaft section with theelectrodes being electrically connected to separate electricalconductors which extend to the proximal section of the elongated shaft.3. An intravascular assembly, comprising:a) an elongated catheter havingan elongated shaft comprising a tubular member formed of braided strandswhich include a plurality of electrical conductors, proximal and distalends, a port in the proximal end, a port in the distal end, an innerlumen extending within the elongated shaft to and in fluid communicationwith the ports in the proximal and distal ends, a distal sectionconfigured to be advanceable through a coronary artery or cardiac veinof a patient's heart, a plurality of sensing electrodes mounted on andlongitudinally spaced along a length of the distal section thereof andwith each electrode being electrically connected to a said electricalconductor; and b) an elongated guidewire device slidably disposed withinthe inner lumen of the elongated catheter, comprising: an elongatedshaft having proximal and distal sections with the distal section beingconfigured to be advanceable through a coronary artery or a cardiac veinof a patient's heart and having a core member extending to a distalextremity thereof and forming at least in part a shapeable flexibleguiding tip.
 4. An intravascular assembly, comprising:a) an elongatedcatheter having an elongated shaft comprising a tubular member formed ofbraided strands which include a plurality of electrical conductors,proximal and distal ends, a port in the proximal end, a port in thedistal end, an inner lumen extending within the elongated shaft to andin fluid communication with the ports in the proximal and distal ends, adistal section configured to be advanceable through a coronary artery orcardiac vein of a patient's heart, a plurality of electrodes mounted onand longitudinally spaced along a length of the distal section thereofand with each electrode being electrically connected to a saidelectrical conductor; and b) an elongated guidewire device slidablydisposed within the inner lumen of the elongated catheter, comprising:anelongated shaft having proximal and distal sections with the distalsection being configured to be advanceable through a coronary artery ora cardiac vein of a patient's heart and having a core member extendingto a distal extremity thereof and forming at least in part a shapeableflexible guiding tip.
 5. The intravascular assembly of claim 4 whereineach electrode is electrically connected to a separate electricalconductor.
 6. The intravascular assembly of claim 5 wherein theelectrodes on the guidewire device are electrically connected toseparate electrical conductors which extend to the proximal section ofthe guidewire device elongated shaft.
 7. The intravascular assembly ofclaim 4 wherein the guidewire device includes a plurality of electrodesmounted on the distal shaft section thereof.
 8. An intravascularcatheter, comprising:a) an elongated shaft having proximal and distalsections and a lumen extending therein configured to slidably receive aguidewire, with the distal section being configured to be advanceablethrough a vein or artery of a patient's heart, and the shaft including atubular member formed of braided strands which include a plurality ofinsulated electrical conductors, b) at least four electrodes mounted ona length of the distal section with the electrodes having asubstantially uniform interelectrode spacing and being secured to thetubular member, and c) at least one electrical connector on a proximalend of the shaft which has separate electrical connecting meansconnected to the individual electrical conductors.
 9. The intravascularcatheter of claim 8 wherein each electrode is electrically connected toa separate electrical conductor.